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Just replaced the CPU on my friend's board about a week ago - we both decided to take the plunge and try it out. He took his part of the gamble by buying the CPU itself, since it wasn't exactly cheap and I took my part by taking a shot at replacing it. I HAVE replaced this sort of IC before and was confident to try it again, especially after I pulled off the dead one and all the pads remained intact. It was NOT easy, but it worked out in the end. I also replaced the buck regulator IC with the 2A version to hopefully make it more robust...we'll just have to see how long it lasts...
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How much was this ? I'm just curious if it's a viable option to fixing one of these (IF it works, that is). If it ends up costing half the price of a replacement board, factoring in the effort required to replace it, I'd say it's not worth it, especially since this is the second board that dies on me (or HIM, since it's my friend's)...
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How I "fixed" the display on an Akai LT-3220AD TV
Good day folks. I thought I'd share with you something I did today, just for a laugh and for a bit of a discussion, since I'm still not entirely convinced what happened there.
I found an Akai LT-3220AD TV in the dumpster - literally - so me and my colleague brought it back into the shop and dusted it off a bit to see if someone maybe gave up too soon.
Long story short: backlight came on but had no picture. My colleague attempted to reprogram the SPI chip but it didn't change anything, so we concluded it must be the panel that's faulty, especially after reading about it...
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Wow....surprised how many of these are failing ! Even more ironic is that the replacement board I got for my colleague less than a year ago ALSO failed just a couple of days ago AGAIN ! Big pen!s-shaped stain on the face of LG here...
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Surprised you even managed to see the D5 mark in the first placebut no - diode's fine.
Ok, problem solved. Take a guess what the big problem was.....seriously, can you guess what the magic component was ?........give up ? Ok, it was the bridge rectifier all along. You can tell it's been ages since I've fixed a SMPS. I forgot to check the most basic of things. Ok, I sort-of checked it, though no thoroughly: I just ran my probes across it and got nothing, so I just assumed it's all good, but it turns out the damn thing was shorted on just ONE of the diodes: AC leg to + leg, which...Last edited by Dannyx; 12-06-2023, 01:46 AM.
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UC3842 Power Adapter Blowing Fuse
Good day folks......wow this new layout is weird. It's like I woke up one day and I'm no longer on Planet Earth or something
Anyway....got this here power brick from a USB to SATA adapter which keeps blowing the fuse after I almost repaired it. The reason I even bother to fix a power brick (wall wart, whatever) in the first place is because this thing was really convenient to use: I'd just plug it and that's it. It's a dual output supply, for both 12v and 5v, which although I COULD easily obtain with a DC-DC converter from a standard 12v adapter, I thought I should crack open the...
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Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)
I think we're done here: tried to apply 3.3v to pin 8 of the 24C512 IC to see if anything might cause the 3.3v regulator to shut down and the smaller die of the CPU began to heat up. I'm not sure this is normal because it doesn't have a heatsink on, but I doubt it'd get that hot...
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Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)
Oops.....Ok, big fail on my sideI was still fixated on the idea that I should try replacing the original 25Q40 SPI chip with something else for testing, like I tried with the Q64, so when I saw C512 on there, it didn't occur to me to read more carefully, so I thought I should now seek out a Q512 IC to try in place of the 25Q40, which is a stupid thing to try because this is the EEPROM we're talking about, which is not only a different physical form factor but also has a different prefix - [I][B]24[/B][/I], instead...
Last edited by Dannyx; 11-15-2023, 02:19 AM.
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Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)
I tried it again today with a different chip but same story, even worse actually. I tried a 25L40 (as opposed to [B][I]Q[/I][/B]40) and apparently it doesn't have the 3 registers (only 1 column shows up in NeoProgrammer, so I can't set 42, only 88). I tried it out anyway just to see what happens and this time I didn't even get the standby LED to come on, so that clearly didn't work. It also tells me there is some communication present, even in this half-dead state, which enables the stand-by state, otherwise the different...Last edited by Dannyx; 11-13-2023, 03:16 AM.
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Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)
I think I did that the second time around. The order looks like this: put chip into programmer>detect it (I choose the closest one)>unlock>erase>blank check>open bin file>write bin file>open "edit SREG" >check the 4 checkboxes, uncheck the last one>hit write. Should I bother to try with a new 25Q40 ?...
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Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)
Ok, I tried it several more times but no success.
I had some issues with ASProgrammer which wouldn't let me tick the QE box for some reason (first screenshot). I then tried NeoProgrammer which did - think there's some issue with the CH341...anyway. I'm sure I did everything right this time: removed chip, unprotected it, erased it, opened dump file, program, checked the 4 checkboxes you indicated and uncheck the one on the far right and hit "write", so I think the CPU's dead or no longer soldered...
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Re: Samsung ue55mu6202k bn94-12778s Not turning on (dump help ?)
I DID try the TV one more time after reading the dump the first time, since I also wiped and re-wrote the chip shortly after, but didn't know what to set in that sub-menu. No change in behavior.
I'm actually curious to see if I NOW get all FFs at the start too when I pull it off to read it again. What were the options that needed ticking in the sub-menu, assuming I write the original dump back ?
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